A flexible printed circuit board (FPC) is a circuit board which can be easily bent and flexible, so that it is commonly used for connecting various parts of foldable electronic devices, such as clamshell phone hinges, etc. Thus, it is important to have a FPC capable of being bended at an exact position where is it is designed to be bended.
As shown in FIG. 1 and FIG. 2, a white line 11 is usually being marked on a conventional FPC 10 at a position where it is designed to be bended and is used for assisting an operator of a bending process to identify the position where the FPC is supported to be bended. However, as there can be tolerance for the marking of the while line 11 on the FPC 10 in addition to the error caused by the manual bending of the operator, accurate control of the bending angle for bending FPC 10 can not be realized.
There are some manufacturers trying to improve the aforesaid bending accuracy by hollowing a portion of their FPCs at positions where it is supposed to be bended, However, such method will damage the FPCs, causing the strength of the FPCs to reduce and sometimes even crack.